IP based voice chat is nothing new. In fact the release of Google talk brought the issue back into the limelight with arguments over which IM (Instant Messenger) was best suited or offered the best voice chatting over IP. This device is called as the IM phone, and is a really simple , easy to use gadget.

You simply plug it into the USB port of your laptop or PC ; it gets automatically detected and then pair it with you cell phone. The IM Fone is compatible with two services at this point of time, imtel and Skype. Both Skype and imtel allow you to call any landline on the planet for a small fee. Needless to say it is very cheap as compared to the normal international tariff that you may have to pay.

The IM fone allows you to use your cell phone and its contacts as usual, the difference being that you are not actually using the cell phone service network but rather the internet to make and recieve these calls. There will be of course major savings in your next bill cycle thanks to the IM fone. Being based on bluetooth, it is possible for the user to move around in a range of 50 meters from the computer with his cell phone and still be able to talk. The best part is that even if you are using the Skype service to make an international call, it is your cell phone number that will be displayed to the caller ID of the other party.

So its not just a fancy device which replaces the mic and speakers, but a pretty useful thing to have while on international travel, unfortunately it works only with selected cell phones.

More here.